Marine drive unit

Abstract

A marine drive unit for a marine vessel has a shaft housing having a housing face and a rotatable shaft having an outer shaft face. The rotatable shaft is rotatable arranged within the shaft housing whereby an annulus is defined between the housing face and the outer shaft face. The shaft housing has an inlet being in fluid communication with the annulus so that a lubrication can be introduced in the annulus. One or more spacer element(s) is/are arranged at the inlet for at least dividing the annulus up in several parts around the inlet.

What is claimed is: 
     
         1 . A marine drive unit for a marine vessel, comprising
 a shaft housing having a housing face,   a rotatable shaft having an outer shaft face, the rotatable shaft being rotatable arranged within the shaft housing whereby an annulus is defined between the housing face and the outer shaft face,   the shaft housing comprising an inlet being in fluid communication with the annulus so that a lubrication can be introduced in the annulus,   wherein one or more spacer elements are arranged at the inlet for at least dividing the annulus up in several parts around the inlet.   
     
     
         2 . The marine drive unit of  claim 1 , wherein the spacer element is arranged around the rotatable shaft. 
     
     
         3 . The marine drive unit of  claim 1 , wherein the spacer element is projecting from the outer shaft face. 
     
     
         4 . The marine drive unit of  claim 1 , wherein a first spacer element is arranged on a first side of the inlet and a second spacer element is arranged on a second side of the inlet. 
     
     
         5 . The marine drive unit of  claim 1 , wherein the spacer element comprises a ring, a ridge, or a protrusion. 
     
     
         6 . The marine drive unit of  claim 1 , wherein the spacer element is made of a metal, a composite, a polymeric, or any combination thereof. 
     
     
         7 . The marine drive unit of  claim 1 , wherein the spacer element comprises a first ring arranged on the first side of the inlet and a second ring arranged on the second side of the inlet. 
     
     
         8 . The marine drive unit of  claim 1 , wherein the rotatable shaft is hollow and has an inner shaft face and a shaft wall extending between the outer shaft face and the inner shaft face. 
     
     
         9 . The marine drive unit of  claim 8 , wherein a second rotatable shaft is arranged inside the hollow rotatable shaft, whereby a second annulus is defined between the inner shaft face and a second outer face of the second rotatable shaft. 
     
     
         10 . The marine drive unit of  claim 9 , wherein the shaft wall comprising a second inlet, the second inlet being arranged between the spacer elements, the second inlet being in fluid communication with the second annulus so that the lubrication can be introduced in the second annulus. 
     
     
         11 . The marine drive unit of  claim 10 , wherein a plurality of second inlets is arranged around a circumference of the rotatable shaft between the spacer elements. 
     
     
         12 . The marine drive unit of  claim 10 , wherein one or more spacer elements are arranged at the second inlet for at least dividing the second annulus up in several parts around the second inlet. 
     
     
         13 . The marine drive unit of  claim 8 , wherein the inlet is in fluid communication with the second annulus via the second inlet. 
     
     
         14 . The marine drive unit of  claim 1 , wherein the rotatable shaft is connected with a propeller and is providing rotation to the propeller. 
     
     
         15 . The marine drive unit of  claim 9 , wherein the second rotatable shaft is connected with a second propeller and is providing rotation to the second propeller. 
     
     
         16 . The marine drive unit of  claim 1 , wherein a distance between the housing face and the spacer element is smaller than 1 cm, preferably smaller than 0.5 cm, more preferably smaller than 0.3 cm. 
     
     
         17 . The marine drive unit of  claim 1 , wherein one or more bearings are arranged in the annulus. 
     
     
         18 . The marine drive unit of  claim 7 , wherein the spacer element comprises a base part connecting the first ring and the second ring, the base part is extending along and around the rotatable shaft. 
     
     
         19 . A marine vessel comprising the marine drive unit of  claim 1 . 
     
     
         20 . A lubrication method for lubricating a marine drive unit of  claim 1 , comprising
 providing one or more spacer elements at the inlet for dividing the annulus up in several parts around the inlet,   supplying a lubrication to the inlet,   building up a pressure in the lubrication at the inlet by the one or more spacer elements function as a barrier,   utilizing the pressure to drive the lubrication towards any components being in fluid communication with the inlet.